1. Field of the Invention
The present invention relates to a driving apparatus including an electromechanical transducer as a driving source.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 7-274544 discloses an example of a technique in this field. A driving apparatus described in this publication includes a driving shaft (non-deforming part) and a lens barrel (driven part). The driving shaft is fixed to an end of a piezoelectric element in an expanding-and-contracting direction of the piezoelectric element. The lens barrel is frictionally engaged with the driving shaft by a pressure-contact spring (friction part) and a friction plate (friction part). When a pulse voltage is applied to the piezoelectric element, the piezoelectric element expands and contracts so as to move the driving shaft. As a result, the lens barrel, which is frictionally engaged with the driving shaft, is moved.
However, in the above-described driving apparatus, the expanding-and-contracting direction of the piezoelectric element is the same as the direction of an optical axis of a lens. Therefore, the piezoelectric element, the driving shaft, and a support plate for supporting the piezoelectric element and the driving shaft are arranged in the optical axis direction. Thus, the dimension of the apparatus in the optical axis direction is relatively large, and it is difficult to reduce the thickness of the driving apparatus.